MZ11/MA61 Digital Dash issues! HALP!

[Admiral coFF33]

I have speedo issues with my digi dash

I have been sitting at work now from 7am - 11am reading tech section threads on speedos electronic and what not in other cars and issues people have had. but.....

Ok im gonna try and post this as clear as possible and remember as much as i can right now.

ill start with saying this:

car : MZ11 - 1981
dash : MZ11 - 1981 Digital
Drive : W55 cable drivin -> dash



When driving, some days (most of the time i find if the air temp in perth is 35+ and my car has been on the street while ive been at work and its REALLY hot inside) the speedo will work
90% of the time the speedo sits on 0 and does not work

The cable i have replaced and it does rotate when car is in forward and reverse movement.

The odo DOES work (small and large odo) therefore the issue is electronic


Yesterday i opened the dash up, completely.
i removed sections of the dash, tacho, speedo LCD, fuel LCD , Temp LCD, they all come out in different sections and are easy to remove and replace etc.

I found NOTHING out of the ordinary, no splits on the green PCB thing on the back, no burns anywhere, no wires snapped.... nothing

The "Hall Effect Sender" which the cable plugs into was my main point of concern.
I examined it, and it has 3 wires coming out. Yellow, Blue and Green

I connected what i call the "Hall Effect Sender" section where the cable would connect, to a drill. and on a slow speed attempted to get readings off one of the 3 wires with my multimetre.

I got nothing




Out the back i found the 1984 GZ10 dash i removed from the donor car i had a few months back, took it apart and removed the "Hall Effect Sender" from it.

This one is setup EXACTLY the same, but has Yellow, Red and Blue wires coming from it that connect into the 84' dash. Also, the connecter on the end is different.

I ran the same tests with the drill on this one, and had the same results.

I do remember the speedo working fine in the 1984 GZ10 i removed the dash from
and cant remember exactly if the MZ11's dash worked before i did the 1GGTE conversion.



either way.

Does anyone else know what i can test to figure out what wire is what ???
as i have a plan...

I want to externally mount the 84' Hall Effect Sender behind the dash with the speedo cable connected and then CHOP the 3 wire plugs off each one as they are different and connect the 84' sender to the 81 dash to see if that is the issue.

Does anyone know anything about these, or what wires would generally be what ?

is there another way im not sure about , to test these ?

Halp

<3 coff

(ps. sorry bout the essay)

[Cuzzo]

Out the back i found the 1984 GZ10 dash i removed from the donor car i had a few months back, took it apart and removed the "Hall Effect Sender" from it.

This one is setup EXACTLY the same, but has Yellow, Red and Blue wires coming from it that connect into the 84' dash. Also, the connecter on the end is different.

I ran the same tests with the drill on this one, and had the same results.

I do remember the speedo working fine in the 1984 GZ10 i removed the dash from
and cant remember exactly if the MZ11's dash worked before i did the 1GGTE conversion.

Did you try to drill in forward and reverse?

[JustCallMeOrlando]

Are you able to power up the 84 dash and then find out which wires are being fed power and earth, which will give you your signal wire. You'll be hard pressed to see the pulses with a digital multimeter. It'd at least mean you could jimmy up your 81 speedo sensor to the 84 dash to see if it works.

[Admiral coFF33]

Did you try to drill in forward and reverse?

yes

10chars

[Admiral coFF33]

Are you able to power up the 84 dash and then find out which wires are being fed power and earth, which will give you your signal wire. You'll be hard pressed to see the pulses with a digital multimeter. It'd at least mean you could jimmy up your 81 speedo sensor to the 84 dash to see if it works.

Id like to think i could but i have none of the loom from the previous soarer (now crushed) so wouldnt have a clue what goes where on the back of the 84' dash

[JustCallMeOrlando]

Pull it apart

[takai]

I can check my MA61 one when i get home, its in bits in a box.

[Admiral coFF33]

Takai!

if you do remember and can post results here i will forever love you

i know ur good at wiring, so what you say ill go with.

also im assuming MA61/GZ10 (1984 era) will have same same Sensors / wirecolours...

[Admiral coFF33]

Also

MA61 :




That diagram is sotra showing what pins are what ????

Si being signal ???

hrmmm

i wonder if this is the case for my 81' plug connector

[toyoda]

Hi,


May not be applicable but are you sure its not :

1/. Reed Switch type - unlikely as it is 2 wire
2/. Photocoupler Type - Possible as it is 3 wire ( 5 volt in - Ground - Signal out pulsed )
3/. MRE Magnetic Resistance Element - Also 3 wire ( 12 volts in - Ground - Signal out pulsed)

If you give me an Email Address I can probably arrange for someone to Email you the refernce book.

Toyoda

[Admiral coFF33]

Toyoda.

Im not sure what so ever

in 4 - 5 other threads i read this morning
others were calling it a Hall Effect Sender

And going by wiki / google. this is setup the same when i look at it with my shitty electronic know-how

[Admiral coFF33]

Although going by the little i know of electronics in cars.
For example a Water temp gauge (elec)

Req. Power, Ground, Negative.

Sending power to the top pipe sensor
Grounding the top pipe sensor / housing
Signal wire coming from the top pipe sensor to the electronic gauge mounted on my dash



This theory makes me think that there is power + ground + sensor and thats what the 3 wires are

the issue is

yellow blue green

and

yellow blue red


what could be what ?

Blue im guessing is signal
yellow....
green....
red ....

[toyoda]

Well, the Ground and Power are easy -

Continuity test to ground and
Voltage test with ignition on.

Toyoda

[Admiral coFF33]

Would be easy, if i could access behind the dash whilst it was connected to loom...
but cant

so cannot test with ACC/Ign on....

:S

any other ideas ?

Can i do continuity to find out negative and positive on 2 pins ?

[toyoda]

No need to connect it - just measure straight at loom connector for Ground and power.

Toyoda